check default values for encode/decode

[pyramation]

I've seen some with 0, Long.UZERO, but now some that are undefined.

      nullValue: isSet(object.nullValue) ? nullValueFromJSON(object.nullValue) : 0,
      boolValue: isSet(object.boolValue) ? Boolean(object.boolValue) : false,
      int64Value: isSet(object.int64Value) ? Long.fromString(object.int64Value) : undefined,
      uint64Value: isSet(object.uint64Value) ? Long.fromString(object.uint64Value) : Long.UZERO,
      doubleValue: isSet(object.doubleValue) ? Number(object.doubleValue) : undefined,
      stringValue: isSet(object.stringValue) ? String(object.stringValue) : \\"\\",
      bytesValue: isSet(object.bytesValue) ? bytesFromBase64(object.bytesValue) : new Uint8Array(),
      durationValue: isSet(object.durationValue) ? Duration.fromJSON(object.durationValue) : undefined,
      timestampValue: isSet(object.timestampValue) ? Timestamp.fromJSON(object.timestampValue) : undefined

both unsigned and signed zeros

• UZERO
• ZERO